The present invention relates to electron-beam metrology including a standard reference for metrology used in electron-beam metrology.
Standard references for metrology for electron-beam metrology according to the prior art use a grating which is fabricated over a semiconductor substrate by laser interferometer lithography and anisotropic chemical etching. Their calibration is accomplished by measuring the diffraction angle of grating by the use of a laser beam whose absolute accuracy is guaranteed (see, for instance, Japanese Patent Application Laid-Open No. 7-71947).